Posture. Can you write a Golf Book and not once use the word..... "Posture"?
The TGM Golfer in the illustration below is using the "Turned Shoulder" Plane. The Traditional Golfer is using the "Elbow" Plane.
Below are a couple of ideas about posture and TGM compared to the Traditional approach to Golf Swing and Plane Control. Golf Strokes with the greatest mechanical advantage include an On-Plane Right Shoulder at the Top of the Swing and an On-Plane Right Shoulder during the Downstroke. In TGM, the Right Elbow Controls the Right Shoulder Location during and at the Top of the Backstroke. Plane Angles for longer and shorter Clubs are compensated by changes in Power Package Alignments. The significant alignment of the Power Package is the amount of Bend in the Right Arm. More Bend for Longer Clubs and less bend for shorter Clubs. More bend causes shallower planes and less bend causes steeper planes. All of these are Turned Shoulder Planes and all of these are controlled automatically at Address and by the Right Forearm-Extensor Action Takeaway. It doesn't get any easier than that.
Tradition has Golfers adjust their Posture for each Length Golf Club. More upright stance for longer clubs and more bent over for shorter clubs. An indication of Pivot Controlled Hands Procedure. When a Traditional Golfer arrives at Impact and has been fortunate enough to have his Right Forearm On-Plane to support and Guide the Clubhead, he has forced significant posture re-Alignments during the Swing. I wonder what the Bio-Mechanics people would say about that?